Manifolds may be used to control flow. For example, a stream of air may be divided into a number of separate streams. In the case of an intake manifold for use with an internal combustion engine, the separated streams may be passed toward a corresponding number of combustion chambers of a multi-cylinder internal combustion engine. Intake manifolds occupy space in the engine compartment, and they must be constructed strong enough to withstand strong and changing differential pressures on the walls that form flow passages therein. They must also be stiff enough to avoid excessive vibration that may contribute to engine NVH (Noise, Vibration, and Harshness). Intake manifolds typically include circular runners for strength. However, circular runners add length and/or depth to the manifold. Runners with flat sections tend to be weak and prone to vibration. External ribs extending substantially parallel to the external surfaces may be used to add strength and stiffness. However, these external ribs add to the overall volume occupied by the manifold in the engine compartment.
U.S. Pat. No. 2,587,360 to Milbrath discloses an intake manifold with internal vanes. These vanes are located where the air is divided between manifold branches to control erratic turbulence. However, even with turbulence reduced, a manifold with flat portions can still cause excessive NVH.
The inventors herein have taken an approach that reduces the space taken up by the intake manifold while still avoiding excess NVH. Embodiments in accordance with the present disclosure may provide an intake manifold that may include a plastic shell defining an intake passage in fluidic communication with a runner configured to pass inlet air to a combustion chamber. The runner may have a substantially flat inner surface. The intake manifold may also include one or more ribs disposed along the inner surface. The one or more ribs may have a length extending along a portion of the inner surface in a direction substantially corresponding to a flow direction.
In this way, flat portions of the runners may be made stronger by the one or more ribs disposed along the inner surface with little to no disruption to the flow. In this way embodiments in accordance with the present disclosure may provide an intake manifold having a number of runners with substantially rectangular cross sections. The substantially rectangular cross sections may reduce the overall, height, i.e. thickness, of the manifold. In addition, some embodiments in accordance with the present disclosure may include runners that at least partially overlap in a vertical direction. In this way the overall length of the manifold may be reduced.
The present disclosure may use perspective-based descriptions such as up/down, back/front, and top/bottom, and/or orientation-based descriptions such as height, width, length and thickness. Such descriptions may be used to describe presently disclosed embodiments, and/or may be used in the description of other disclosures in a comparative way, and may merely be used to facilitate the discussion and are not intended to restrict the application of embodiments disclosed herein.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.